1. Field of the Invention
The present invention relates to a solid electrolytic capacitor and a method for manufacturing the same.
2. Description of Related Art
A solid electrolytic capacitor is generally configured by: anodizing an anode made of a valve metal, such as tantalum or niobium, thereby forming a dielectric layer mainly made of an oxide on a surface of the anode; forming an electrolyte layer on the dielectric layer; and then forming a cathode layer on the dielectric layer. In such a solid electrolytic capacitor, it is preferable that its equivalent series resistance (ESR) be small.
As a method for decreasing ESR, proposed is a formation of an electrolyte layer made of a conducting polymer. Specifically, Japanese Patent Application Publication No. Hei 10-321471 proposes formations of: a first conducting polymer layer made of polythiophene or a derivative thereof; and a second conducting polymer layer made of polypyrrole or a derivative thereof on the first conducting polymer layer.
However, the solid electrolytic capacitor with the conducting-polymer electrolyte layer formed therein has a problem that, when the solid electrolytic capacitor is preserved under a high-temperature condition, adhesiveness between the dielectric layer and the electrolyte layer decreases, thus causing a decrease of capacitance.
Accordingly, an object of the present invention is to provide a solid electrolytic capacitor with excellent preservation characteristics under a high-temperature condition and a method for manufacturing the solid electrolytic capacitor.